Studies on the effects of chromium supplementation on the metabolic response to exercise

Chromium is one of the essential dietary trace elements that an important role in regulating whole body metabolism and energy utilization. However, there is a strong argument about chromium supplementation during exercise training programs, as some authors recommend it and others consider it illegal. Therefore, this work was planned to assess the metabolic responses to exercise training program in conjunction with chromium supplementation. Four rat groups were studied; rats subjected to swim exercise 2 hours/day for 2 weeks, rats supplemented with chromium picolinate in a dose of 90 micro g/kg body weight/day by gavage for 2 weeks and rats exposed to both regimens as well as their control non-exercised non-supplemented rats. Results of the present study revealed improvement in glucose tolerance with insignificant changes in serum insulin concentrations and a remarkable hypolipidemic responses in the three studied rat groups compared to the control. Unexpectedly the metabolic responses of the combination of chromium and exercise training did not exceed those obtained either chromium supplementation alone or exercise alone. Such non-additive effect could be ascribed to the common pathway shared by both chromium and exercise to exert their actions; and either chromium or exercise could, on its own, achieve the maximal response that cannot be further increased by their combination. The beneficial effects of chromium supplementation on increasing insulin sensitivity and improving blood lipid profile makes it an effective agent in treating non-insulin dependent diabetes and arteriosclerosis. Also, chromium has favorable effects in sparing protein use during exercise, decreasing lactate production with conservation of high glycogen content that enables prolongation of strenuous muscular exercise and much delaying the exhaustion point. In conclusion, it is evident from this study that chromium is instrumental in mediating metabolic effects of exercise and its role, in this respect, is physiological not pharmacological. Therefore, it is wrong to deal with chromium as one of the ergogenic substances that considered illegal to use with exercise

Chromium, the natural lipid-modulating therapy, protects the rat myocardium against ischemic-reperfusion hazards

This study was carried out on 20 male albino rats weighing 200-250 grams each. They were divided into 2 groups: Group I [n = 10], used as control; Group II [n = 10], chromium supplemented rats at a dose of 20 micro g/ rat/day for 12 weeks. After that, blood samples were collected for estimation of serum triglycerides [TG], total cholesterol [TC], high density lipoprotein-cholesterol [HDL-C] as well as fasting glucose and insulin levels. This was followed by ischemia-reperfusion of isolated hearts. After 30 minutes of reperfusion, the hearts were sent for histopathological examination, LDL-cholesterol [LDL-C] and HDL/total cholesterol ratio were also calculated. The results of this study showed that chromium supplementation induced significant reduction in the levels of serum glucose, insulin, TG, LDL-C and TC accompanied by a significant increase in HDL-C and HDL-C/TC ratio. Chromium supplemented hearts, also showed better recovery of myocardial activity at different periods of reperfusion compared to control hearts in the form of a significant increase in heart rate [HR], peak tension [PT] and myocardial flow rate [MFR] as well as an insignificant reduction in time to peak tension [TPT] and half relaxation time [1/2RT]. Histopathological examination of hearts showed a clear picture of ischemia in control hearts compared to chromium supplemented hearts. We can conclude that chromium supplementation can protect the rat myocardium against ischemic-reperfusion hazards and this may be due to promoting the healthy blood lipid level and reducing fasting insulin levels which may reflect enhancement of tissue sensitivity to insulin